The present invention relates to the field of ion implanters used in semiconductor manufacturing.
In ion implanters, it is known to employ components to measure the ion beam current. In one known configuration, components called “Faraday cups” are located at the far end of the evacuated chamber in which the ion beam travels. The ion beam strikes each Faraday cup and creates a corresponding current in an external circuit connected to the Faraday cup. This current is measured and converted into a measure of ion beam current. By using multiple Faraday cups in an arrayed fashion, it is possible to obtain a measure of total beam current (by summing the currents generated from each of the cups) and a representation of the spatial distribution of the beam current. This latter aspect can be useful in shaping and steering the beam accurately.
The connections between the Faraday cups and the external current-measuring circuitry must pass from the high-vacuum internal environment of the ion implanter to the outside operating environment, which is typically at atmospheric pressure. Moreover, the connections must be electrically isolated from the metal walls of the implanter, which are typically connected to a high-voltage source. It has been known to employ specialized feedthrough connectors that are suitably gas-tight at high vacuum and that provide the necessary electrical isolation. Such feedthrough connectors typically have a ceramic body or outer shell with an internal conductive element. The ceramic body is mounted in gas-tight fashion in an opening of a wall of the ion implanter. A connection is made between a Faraday cup within the implanter and one end of the feedthrough connector, and another connection is made between the external circuit and the other end of the feedthrough connector. Where an array of Faraday cups is employed, multiple feedthrough connectors and/or a feedthrough connector with multiple conductive elements are used to provide the necessary plurality of connections.